Lam Research Corporation

David R Arnett

Ching-Hwa Chen

David R-Chen Liu

Jeffrey V Musser

A method in a substrate processing chamber for forming a conductive feature by etching through a conductive layer disposed above a semiconductor substrate. The method includes etching at least partially through the conductive layer using a first etch recipe to form a top portion of the conductive feature. The method further includes thereafter etching at least partially through a remaining thickness of the conductive layer using a second etch recipe different from the first etch recipe to form a bottom portion of the conductive feature. The bottom portion is disposed below the top portion. The second etch recipe is configured to yield a sloped etch foot in the bottom portion of the conductive feature.

Methods and apparatus for etching a conductive layer to improve yield

A plasma cleaning method for removing residues previously formed in a plasma treatment chamber by dry etching layers such as photoresist, barriers, etc., on a wafer. The method includes introducing a cleaning gas mixture of an oxidizing gas and a chlorine containing gas into the chamber followed by performing a plasma cleaning step. The plasma cleaning step is performed by activating the cleaning gas mixture and forming a plasma cleaning gas, contacting interior surfaces of the chamber with the plasma cleaning gas and removing residues on the interior surfaces. The cleaning gas mixture can also include a fluorine-based gas. For instance, the cleaning gas can include Cl.sub.2 and O.sub.2 and optionally CF.sub.4. An advantage of the cleaning method is that it is not necessary to open the plasma treatment chamber. Also, it is possible to completely remove all residues and prevent by-products formed during the cleaning step from remaining after the cleaning step.

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Fremont, CA, United States of America

David R Arnett